Ipomoea pterocaulis J.R.I.Wood & L.V.Vasconc.

Wood JRI et al. 2017. New species of Ipomoea (Convolvulaceae) from Bahia. Kew Bulletin 72:8. DOI 10.1007/S12225-017-9678-5

Type

Type: Brazil, Bahia, Morro do Chapéu, c. 1 km após Lagoinha na Estrada para Cafarnaum, 11°41'01""S 41°20'11""W, 902 m, L. P. de Queiroz, J. R. I. Wood & H. Huaylla 15957 (holotype HUEFS 209791; isotypes K, OXF).

Morphology General Habit

Vigorous twining plant decumbent in open ground or climbing over bushes to several metres, stems stout, prominently winged, glabrous

Morphology Leaves

Leaves petiolate, 2.5 – 10 × 2 – 9 cm, ovate-deltoid, acute or obtuse, base shallowly cordate with a broad sinus and rounded to subacute auricles, margin undulate to slightly sinuate, both surfaces glabrous, abaxially paler with prominent veins; petioles 1.3 – 5.5 cm

Morphology Reproductive morphology Inflorescences

Inflorescence of pedunculate axillary cymes; peduncles 2 – 12 cm; bracteoles 1 – 2 mm, lanceolate, caducous; secondary peduncles 1 – 2 cm; pedicels 3 – 5 mm; sepals subequal, glabrous, 13 – 15 × 7 – 10 mm, elliptic, obtuse rounded; outer often reddish, inner with scarious margins; corolla (6 –) 8 – 9 cm long, glabrous funnel-shaped, tube white; limb 7 – 8 cm diam.; stamens and style held at mouth of corolla; filaments unequal, glabrous except for the hairs at the base, longer pair 8 – 15 mm, shorter filaments 3 – 5 mm; style glabrous, stigma biglobose

Morphology Reproductive morphology Fruits

Capsule 10 × 8 – 9 mm, ellipsoid, glabrous, muticous; seeds 6 × 4 mm, dark brown, glabrous except for long white hairs on angles

Note

This is a conspicuous species because of its large corollas and frequent occurrence in open habitats. Particularly distinctive in the field are its winged stems. This might suggest a link with Ipomoea subalata Hassl. from Paraguay but the glabrous corolla, leaves and sepals immediately distinguish it. It has been identified in herbaria as I. jalapa (L.) Pursh. but can be easily distinguished by its glabrous stem, sepals and corolla. It also differs in its seeds which are glabrous with long white hairs on the angles rather than pilose with hairs of different lengths. It has also been compared with I. asarifolia (Desr.) Roem. & Schult. but is easily distinguished by the ovate-deltoid, cordate leaves (not suborbicular to reniform), the subequal (not very unequal) sepals and the seeds pilose on the margins (not minutely and uniformly tomentellous). Unpublished molecular studies place it in a clade with I. connata and slightly more distantly with Ipomoea rosea Choisy and I. graniticola J. R. I. Wood & Scotland with none of which does it have obvious morphological affinities except for the glabrous leaves, sepals and corolla. The epithet pterocaulis, meaning “winged stem” refers to the distinctive winged stems characteristic of this new species. NOTES. R. M. Harley et al. 16476 is slightly different from the other collections in having shorter sepals about 10 mm long and is included with a degree of uncertainty.

Ecology

Observations by one of us (JRIW) and notes on herbarium labels suggest this is a plant of sandy soils in open, disturbed caatinga. It is scattered in occurrence and extends from Bahia into Pernambuco State. The recorded altitudinal range is from about 300 to nearly 1100 m.

Conservation

This species is known from at least six distinct locations and in the location observed by JRIW was well-established in open disturbed sandy ground including an area of cultivation of Cajanus cajan (L.) Huth. It is probably not under threat of any kind but in the absence of any evaluation of the different populations it can only be classified as Data Deficient (DD) within IUCN (2012) guidelines.

Phenology

Flowers and fruits from February to September.